The present invention relates to an alarm device to prevent the theft of computers or microprocessor controlled equipment that remain stationary in use. The alarm becomes active and emits a sound whenever the computer or equipment is moved from its stationary position.
There is currently a number of alarm or security devices in the marketplace that become activated upon movement of a computer or appliance. The U.S. Pat. Nos. 4,686,514 and 4,494,114 disclose two such security devices. The U.S. Pat. No. 4,686,514 to Liptak uses an internal alarm which is armed and disarmed through an external key lock. The alarm becomes energized when the AC power supply of the appliance is disconnected and the appliance is physically moved from its normal stationary position. The alarm continues to sound until the appliance is moved back to a stationary position. Liptak's alarm device suffers from a number of disadvantages. First, the device can only be used for wallpowered computers and cannot be adapted for portable computers. Second, the external key lock warns the potential thief that the computer has an alarm and the thief may be able to defeat or destroy the manually operated key lock. And finally, the key lock presents problems as to how many keys are issued and to what personnel, re-keying the lock when one key is lost, and possible duplication of keys by nonauthorized personnel.
The U.S. Pat. No. 4,494,114 discloses a security device that uses a password entered through a keyboard of the microprocessor-based appliance to enable the appliance to be used. If a disabling event occurs to the appliance the security device renders the appliance inoperative. This security device also suffers from a number of disadvantages. First, the appliances must be manufactured with the security device pre-installed. This means that existing computers would not be able to be adapted or modified to include this security system. Second, the security device assumes the potential thief is familiar with the particular appliance and its security system and would not steal the computer or appliance because they would not be able to make the equipment operative. Such previous knowledge may be an inappropriate assumption for many thieves and the security device would become an ineffective theft deterrent. And finally, the password must be given to all of the personnel that use the equipment rather than limiting the password to the personnel authorized to move the equipment and allowing many other people to use the equipment.